Well surveying instrument



Dec. 28, 1943.

' HENRI-GEORGES DOLL 2,338,028

WELL SURVEYING INSTRUMENT Filed Dec. 17, 1940 2 Sheets-Sheet 1 INVENTORU 5 m n 8 N 8 R 9 .o w Mon e. A L r 1 mm 1943- HENRI-GEORGES DOLL WELLSURVEYING INSTRUMENT Filed Dec. 17, 1940 2 Sheets-Sheet 2 INVENTOR HenriGemyaaflall and more particularly separate trips into the thewel1werematic-in opera Patented as. 28,1943

Henri-Georges Doll, Houston, Tex, assignor to schlum burger WellSurveying Corporation,

Houston, Tex, a corporation of Delaware Applhation Decemb r 17, 1940,Serial No: 370,466

This invention relates to bore hole surveying, to means for determininthe inclination of a bore hole and the direction of such inclination atany desired point or points therein.

More specifically, surveying apparatus in which a photographic record isobtained in the bore considerable vfinancial lossto the drilling cominsurveying is essential puny. Good accuracy because acute problemsinvolving p perty rights, stmctural pomtions. and sub-surface mappingare generally solved on the basis of surveys.

Heretoi'ore, it has been the practice ii) make bore hole for eachservicing operation to be effected. This was done in ordertoenableonetypoiapparatustobere- For this reason, two trips into in order to make anelectrical log and a survey of the inclination of a well.

Moreover, some difliculty has been experienced in obtaining accurateresults surveying apparatus. In certain water-fight housing and isautotiming mechanism being used to eflect this been ioimd to bedisadvantage us in that the sequence or cannot be controlled orvarledonceamnhasbeenstarted, and there is no way of knowing whether theunit is operating properly or not without bringing it back to-thesurface.

Accordingly, it is an object of this invention to provide a veryaccurate surveying t which may be run into the hole with other apparatus such as, for example, an electrical logging device to enableboth a survey and an electrical log to be obtained on a single trip intothe bore hole, thereby greatly reducing lost rig time.

Another object of the invention relates to well with prior wellresult.This arrangement has the total this invention is'to provide connectionsfor additional cable and another type for carrying .out, adifferentoperation to be substinot require a 7 claims- (Ci. 33-2055) of exposure,and making instruments are each completely controlled from the surface.

A further object of this invention is to provide the surface whichconindicates which function the instrument is ready to perform, theindicator being instrument in the bore hole., Another object ot thisinvention is to provide of the film, the length tinuously timingmechanism either in the bore hole instrument or at the surface.

Still another object or this invention is to provide a which neither thetime of the first recording nor the interval between recordings ispredetermined, these times I kiurther object of this invention is toprovide a multi-shot surveying instrumentin which the spacing of therecords on the film may be made equal and. is not influenced by thethickness of the film nor the diameter of the roll of him.

Another object of this invention is to provide a surveying instrumentwhich denotes the movement of the him to the observer, therebyindicating abnormal conditions such as sticking oi to identity the awell surveying instrument constructed according to the presentinvention;

Fig. 2 is a partial view in vertical section, taken along line 22 ofFig. I, looking in the direction of the arrows and illustrating moreclearly the film control mechanism and the .film operated switchingmeans;

Fig.3 is a typical record made by the instrument;

Fig. 4 is a schematic wiring diagram of the circults employed in theapparatus shown. in Figs.

an improved photographic surveying instrument riot only is the sequenceor operations started from the surface, but also individual operationssuch as the movement of the him. the exposure .actuates cam operated iand 2; i

Figs. 4A, 4B and 4C are partial schematic diagrams of. circuitsillustrating the'cycle of operation of the apparatus; and I Fig; 5 is asimplified modification of-the wirins diagram of Fig. 4.

The surveying instrument consists essentially of a watertightnon-magnetic case strong enough to withstand the pressures to which itis subjected, a motor to drive the film, which in turn switching means,a compass, a ball rolling on-a surface of revolution, means forphotographing the position oi the multi-shotc surveying instrument inbeing varied according to the will or the operator.

the invention is to provide derstood by referring to the non-limitingexample illustrated in the figures. Referring to Fig. 1, the wellsurveying instrument comprises a cylindrical casing l8, made of brass orother suitable material, within which is disposed a framework II onwhich the respective elements are mounted.

At the lower end of the casing I is provided a transverse closure member|2, below which is formed an internally threaded skirt portion |3whereby the well surveying instrument may be threadedly secured toanother assembly, if desired, The upper end of the casing I8 is open andit has a shouldered portion |4 adapted to seat a laterally extendingflange l5 formed at the lower extremity of an externally threaded headpiece I6, by means of which the instrument may be attached to anelectric cable or other apparatus (not shown). In order to provide awatertight joint, a gasket ll of rubber or other suitable material isplaced over the flange l5 and a ring I8 is screwed down tightly over itinto the internally threaded upper portion of the casing ID. The ring l8and the casing |0 are provided with suitable recesses I 8 for receivingspanner wrenches to assemble and disassemble the unit.

The circuit for controlling the well surveying instrument, which will bedescribed in detail hereinafter, includes three conductors 20, 2| and22' which pass through insulated bushings 23, 24 and 25, respectively,in corresponding bores 26, 21 and 28 formed in the head piece I 6. Thebush ngs 23, 24 and 25 are retained in position by the screws 29 and 30which are threaded on the conductors 20, 2| and 22 as shown in thefigure. For the sake of clearness, the electrical connections betweenthe conductors 28, 2| and 22 and the apparatus have not been shown inFigs. 1 and 2. 1

At the lower extremity of the casing III, the conductors 20, 2| and 22pass through insulated bushings 3|, 32 and 33 respectively, set incorresponding bores 34, 35 and, 36, respectively, in the closure memberl2, to the interior of the skirt portion l3, where they may be connectedto other apparatus threadedly secured to the casing Ill, if desired.When the well surveying instrument is used alone, conductors 28, 2| and22 are connected together within the skirt portion l3 and a bullet nosedplug is screwed into the skirt portion l3, The plugis not essential, butit facilitates the lowering of the instrument into the bore hole.

Attached to the framework II is an electric motor 31, on the shaft ofwhich is mounted a gear 38 which is adapted to drive a gear 38 securedto a crank arm 46 journaled in the bear- 111g 40a in the-framework Thecrank arm 40 is adapted to be received snugly within a U- shaped slot 4|(Fig. 2) formed at the upper extremity of an arm 42 which is pivotallymounted intermediate its ends at a point 43 on the framework II. It willbe apparent that when the motor 31 is energized to rotate the crank arm40, the arm 42 will oscillate periodically about the pivot point 43.

At the lower end of the arm 42 is fixed a pawl 44 which is adapted toengage a ratchet wheel 45 keyed on a rotatable shaft 46 journaled in theframework l. The pawl 44 is maintained in yielding engagement with theratchet wheel to be actuated by the cam 59 a block 49 mounted on theframework I, which serves as a brake and permits the ratchet wheel toturn in the direction of the arrow only. The shaft 46 on which theratchet wheel 45 is mounted is provided with a longitudinally extendingslot 50 (Fig. 1) within which the end of a strip of film 5| is adaptedto be received. A conventional type film can 52 is mounted over theshaft 46 and it receives the exposed film and protects it while therecord is being removed.

The strip of film 5| is drawn from a second conventional type film can53 which is mounted in the framework beneath the film can 52 and itpasses over spaced apart horizontally disposed rollers 54 and 55 whichare located adjacent the boundary of an aperture 56 through which theinclination indicating means to be described below may be viewed.

The film strip 5| is provided with conventional perforations along atleast one edge thereof which perforations are adapted to be engaged bythe teeth 51 on a sprocket wheel 58 which is rotatably mounted on theframework intermediate the film cans 52 and 53. On the shaft of thesprocket 58 is mounted a cam 59 which is adapted to cooperate with aswitch 60 also mounted on the framework The switch 60 is provided with amovable spring arm 6| which is adapted to move an insulating member 62formedon a spring contact arm 63, causing the contact arm 63 to makeeither of two contacts 63a or 63b dependingupon the position of the cam59.

The lower portion of the aperture 56 is internally threaded (Fig. 1) toreceive .an externally threaded tubular member 64. The interior v thering wall of the tubular member 64 is threaded to receive an externallythreaded ring 65 within which are mounted a lens 66 and a diaphragm 61having a small aperture 68 formed therein. By turning either to theright or to the left as may be necessary, the lens 66 may be adjusted tofocus the inclination indicating means which is described below on theportion of the film strip 5| disposed directly above the aperture 56.

Secured to the tubular member 64 is a radially extending flange 69 inwhich are mounted one or more electic lights 10 which provide theillumination necessary to light the inclination indicating means, whenthe photographic record is taken. If the lamps 10 are series connectedthen they should preferably be shunted'by resistances II which may alsobe mounted on the flange 69.

.45 by means of a spring 4'! which is secured to the arm 42, A secondspring 48 is secured to formed with an outwardly extending conicalportion 12 which is of such size and shape as to prevent any directillumination from the lamps 18 from impinging upon thefilm strip 5|or-the inclination indicating means disposed below.

The means for providing indications'of the inclination of the bore holecomprises a curved member 13 made of glass or other'suitable materialwhich is seated on an inwardlyextending ring 14 formed within theframework II and on which is disposed a freely rolling element I6,preferably a spherical steel ball. Mounted above the curved member 13 isa second curved member 16, also made of glass or othersuitable'materlal, which is spaced apart from the curved member 13 by aring 11, made of brass, for example, such that the distance between thelower surface of the curved member the curved member diameter of theball 13 very slightly exceeds the 15. The entire assembly is 16 and theupper surface of When the gang switch v and the upper surface of thecurved member 18 are groundin the shape of segments of ellipsoids ofrevolution, and the lower surface of the curved member 18 is providedwith etched circular rings 18 (Fig. 3) which, when viewed from theaperture 88 in the diaphragm 81, indicate the deviation of the axis ofthe casing I8 from the vertical for various positions of the ball 15.Whenever the axis of the casing I deviates from thevertical axis, theball rolls to the lowermost position on the {curved member 18 andprovides an accurate indication of such angular deviation,

The direction of the inclination of the bore hole is afforded by meansof a magnetic compassneedle 80 which is pivotally mounted at the point8| on a member 82 located beneath and coaxially with the curved member13. The member 82 is mounted on pivots 83 and 84 in a gimbal ring 85which is pivotally mounted on an axis at right angles to the axis'of thepivots 88 and 84. A

pendulum 88 is secured to the member 82 below the pivot 8| in suchfashion that the compass needle 80 is maintained in a horizontal planeat all times. To assist in differentiating between the north and southends of the compass needle 88 one end may be painted white and the other4 end black.

In Fig. 3 is .shown a typical record of the inclination and thedirection of the inclination made by the instrument. The position of theball 15 with respect to the circular graduations 18 indicates accuratelythe angular deviation of the axis of the casing I8 from the verticalaxis,

and the position'of the ball 15 with respect tothe compass needle 80indicates the direction of the inclination with respect to the magneticnorth no e.

Fig. 4 is a schematic wiring diagram of a circuit employed when a cablecontaining three or more conductors is used to raise and lower theinstrument in a bore hole and an electrical log and a well survey are tobe made during the same, trip into the bore hole. The portion above thebreak representsthe surface equipment while that below the breakrepresents the circuit of the apparatus lowered into the hole.

Referring to Fig. 4, the circuit includes a source of voltage 81 whichmay be, for example, a battery of about 250 volts, one terminal of whichis connected through a conductor 88, a conductor 88 in the supportingcable and the conductor which forms part of an elecbore hole. The other20 to an electrode 80 trical logging circuit in the terminal of thesource of voltage 81 is connected 8| and a mllliammeter 82 to 84 on agang switch 85.

85 comprises the three con and three corresponding conthrough aconductor the contacts 88 and The gang switch tacts 88, and 84 tact arms81, 88 and 88. when the gang switch 85 is thrown to the left, thecontact arm 81 engages the contact 88 and the contact arms 88 and 88,respectively, are moved out of engagement with the correspondingcontacts 88 and 84. 85 is thrown to the right, the contact'arm 81 ismoved out of engagement with the contact 88 and the contact arms 88 and88, respectively, engage the contacts 88 and 84, respectively. In theneutral position of the gang switch 85, the contact arms 81, 88 and 88are all out of engagement with the respective contacts 88,88 and 8.4.

ductor I84, a conductor fixed resistor I I8.

The contact arm forms a part of the electrical well logging circuitreferred to above. The contact arm 88 of the gang switch 85 is connectedthrough a con- I05 in the supporting cable and the conductor 2| to thecontact arm 68 of the switch 88 which is adapted to be actuated by thecam 58 (Fig. 2) to engage either contact 58a or 83b as indicated above.

The contact arm 81 on the gang switch 85 is connected through avariableresistor I88 of about 300 ohms, for example, to the conductor I04. Thecontact 83a is connected to a third electrode I81 which forms part ofthe electrical well logging circuit and the contact 88b is connectedthrough the lamps 18 to the conductor 28 in the casing l8. g

Connected across the source of voltage 81 is a' voltage divider circuitI88 which comprises variable resistor I08 connected in series with a Theresistor I88 may be of the order of 300 ohms while the resistor H8 isabout 2000 ohms. The variable contact III of the variable resistor I08is connected through a pilot light 2 and a conductor ||8 to the con tact88 on the gang switch 85.

In order to make a well survey with the apparatus described above, theframework II is removed from the casing |8 before the apparatus islowered into the bore hole and film with perforations along one or bothedges such as, for example, 35 mm. movingpicture film is placed in thefilm can58. The film can 58 is then placed in. the framework II and theleading end of the film strip 5| is pulled overthe'rollers 54 and 55,under the sprocket wheel 58 such that the teeth 51 enter theperforations thereof, and into the receiving film can 52 where it isinserted into the slot 58 formed in the shaft 45.

The shaft 45 is then given several turns to ging apparatus has beenattachedbelow the well surveying instrument by means of the lowerintemally threaded skirt portion I8 formed on the casing I0. Theelectrical connections to such electrical well logging operations aremade in the 22, as shown in the circuit diagram of Fig. 4. An electriccable (not shown) is then attached in any conventional manner to theextemally' threaded head piece I5, electrical connections being madebetween the conductors 20, 2| and 22 and the corresponding conductors88, I and I82 (Fig. 4) in the cable.

For the sake of accuracy a long, non-magnetic sinker with or withoutcentering guides is rigidly attached above or below the well surveyinginstrument, but as this plays no part in the operation of the surveyinginstrument it is not shown in the drawings. The apparatus is thenlowered to the desired depth in the borehole "where it is stopped, or asis more customary, if possible,

is lowered below the desired depth and then pulled up slowly to thedesired depth.

It will be assumed that at that instant the switch positions and circuitconnections are as shown in Fig. 4. If it is now desired to obtainindications of the inclination of the well at that the electrode I03,the fluid in the bore hole, the I electrode 90, the conductor 20, thecable conductor 89, and conductor 88.

The motor 31 now drives the gears 38 and 39,

thereby rotating the crank arm 40 and causing the arm 42 to oscillateperiodically and to drive the ratchet wheel 45 by means of the pawl 44.

The rotation of the shaft 45 pulls film from the film container 53 andthe displacement of the film strip I rotates the sprocket wheel 58 andthe cam 59 mounted thereon in the directionindicated by the arrow.

As the cam 59 turns, the spring arm 5| acting through the insulatingmember 52 moves the contact arm 53 on the switch 50 into engagement withthe contact 53b. This completes a circuit (Fig; 4) from the variablecontact I I I on the variable resistor I09 through the pilot light 2,contact 95 engaging contact arm 98 on gang switch 95, conductor I04,cable conductor I05, conductor 2|, contact arm 53 engaging contact 53bon switch 50, the lamps 10, the conductor 20, cable conductor 89, andconductor 88. This circuit is shown in simplified form in Fig. 4A, theresistance of the bore hole liquid between the electrodes 90, I01 andI03 being represented by the resistors Ill. The voltage supplied by thevoltage divider I08 is suflicient to cause the pilot light II2 to burnbrightly but is not enough to cause the lamps to light up because thecurrent required to illuminate them greatly exceeds the current requiredto illuminate the pilot light II2.

As soon as the pilot II2 burns brightly, the

gang switch 95 at the surface of the earth is moved to the neutralposition in which all of the contact arms are out of engagement withtheir respective contacts.

motor 31 and the film strip 5I. The entire assembly is allowed to remainstationary for a short while in order that the compass needle 80 and thespherical ball may cometo rest,'and the gang switch 95 is then thrown'to the left, moving contact arm 91 into engagement with the contact 93,the other two contact'arms 98 and 99 remaining out of engagement withtheir respective contacts 95 and 94.

' For this position of the gang switch 95, the full voltage of thebattery is supplied to a circuit including the conductor 9|,milliammeter .92, contact 93 engaging contact arm 91 on gang switch 95,variable resistor I05, conductor I04, cable conductor'I05, conductor 2|,contact arm 83 engaging contact 53b on the switch 50, the lamps 10, theconductor 20, cable conductor 89 and conductor 88. This circuit appearsin simplifled form in F18. 43 from which It will be seen This opensthe'motor circuit, stopping further movement of both the that the fullvoltage of the battery 81 is applied to the lamps I0 through theresistor I05. The lamps 10 now burn brightly, indirectly illuminatingthe compass needle 80 and the spherical ball 5 15 on the curved member13 and exposing the portion of the film strip 5| which lies adjacent theaperture 55.

Aftera suitable period of time, depending on the length of exposuredesired, the gang switch .10 95 is restored to the neutral position andthe recording of the orientation of the bore hole at that station iscomplete. The variable resistor I00 enables the current in the circuitof the motor 31 to be varied as desired and the variable re- 15 sistorI05 controls the currentin the circuit including the lights 10, as shownin Fig. 4B.

While the instrument isbeing moved to the next station or at any desiredtime, the operator at the surface of the earth next throws the gangswitch 95 to. the right, engaging contact arms 98 and 99, respectively,with the contacts 95 and 9|,

again energizing the motor 31, as indicated above,

causing it to move the film strip 5I. The displacement of the film strip5| again rotates the cam 59 until the spring arm 5I on the switch 50 isreleased, causing the contact arm 53 to disenggge the contact 53b and toengage the contact a. In this position of the switch 50, voltage issupplied from the voltage divider circuit I08 to .a circuit includingthe variable contact III on the variable resistor I09, the pilot lightII2, contact 95 engaging. contact arm 98 on the gang switch 95,conductor I04, cable conductor I05,

the conductor 2|, contact arm 53 engaging contact 53a on switch 50, theelectrode I01, the liquid in the drill hole, the electrode 90, theconductor 20, the cable conductor 89 and the conductor 88. A simplifieddiagram of this circuit is shown in Fig. 4C, the resistance of the bore'hole liquid between the electrodes 90, I01 and I03 being represented bythe resistances II4. Inasmuch as the resistance of the bore hole liquidbetween the electrodes 90 and I01 and the contact resistances of theseelectrodes are now included in the circuit of the pilot lamp II2, thelatter burns rather dimly, thus providing an indication that theconnections are as shown.

The motor 31 continues to rotate until the displacement of the filmstrip 5I causes the cam 59 to move the contact arm 53 on the switch 50into engagement with the contact 53b, and

the pilot light II2 burns brightly at the surface. From this point on,the sequence of operations, 55 as described above, I

a photographic record of the orientation of the bore hole at this secondstation.

If it is desired to make an electrical log after obtaininga photographicrecord of the orientation of the bore hole at the first station, the

gang switch 95 should be moved into the neutral position while the pilotlight is burning dimly. As indicated above and shown in Fig. ;lC, thecircuit at that instant is such that the i gcontact arm 53. on theswitch .50 is in engagement with the contact 53a so that the conductor2I is connected to the electrode I01. Under these conditions, therefore,the cable conductors 89, "I05 and I02 are connected to the electrodes90, I01 and I03, respectively, and conventional ielectl'ical oggingoperations may be carried on ruby removing all of the apparatus abovethe break in Fig. 4 and substituting therefor conventional well loggingapparatus 01 the type disclosed in may be repeated to obtain fled formis shown constant and independent of ther time trying the prior patents,Numbers 1,819,923 and 1,913,293.

As indicated above, if it is desired to use the well surveyinginstrument by itself in a well without auxiliary apparatus, theconductors 1., 2i and 22 (Fig. ,1) should be connected together withinthe skirt portion 13 of the casing i9 and the skirt portion l3 closedoff by a bullet nosed plug as described.

If it is desired touse the surveying instrument alone permanently, thecircuit can be simplified in several respects. Since it may beconvenient to use one set of surface equipment in conjunction with thesurveying instrument as used either with or without auxiliary apparatus,the surface apparatus may be identical with shown in Fig. 4. and shortcircuiting the conductors 20, 2i and 22, the lower end ofthe casing lmay be rounded and closed and the portion of conductor 21 which isconnected to the contact 63a In such case a single pole, single throwswitch may be used instead of the single pole, double throw switch 60or, if preferred, the switch 60 can be employed, leaving the contact631: disconnected. The electrical circuit of this modiin Fig. 5.

The manner of operation of this modification is identical with that ofthe modification shown in Fig. 4 except that the switch 60 has only twouseful positions. In one position, the contact arm 63 is in engagementwith the contact 63b and in the other ment with this contact.Accordingly, the pilot light H2 will be either dark or illuminateddepending upon which connection is made.

It will be apparent from the foregoing that the invention providesanimproved well surveying instrument in which the spacing betweensuccessive records on the film can be maintained theamount of film ineither film can. Moreover, inasmuch as the switch in the pilot lightcircuit is controlled by the displacement of the film strip, if the filmbreaks, jams or runs out, this is immediately indicated to the operatorcan remove the instrument from the bore hole and correct the difficultywithout wasting furto take additional records.

In view of the fact that both the time between successiverecords and thelength of the exposure of the film are controlled from the surface ofthe earth,'a convenient means is afforded for identifying the depth ofthe record made at the various stations in the bore hole. For example,the depth of each station may readily be identified by determining thedepth at which the first record is made and over-exposing the recordmade at each thousand foot interval thereafter. It has also been foundvery practical occasionally to leave an extra space between records, toestablish definitely the depth of each record. To accomplish this,current is supplied to the motor 31 until two cycles of operation arecompleted instead of one;v

Obviously, it is not necessary to make a complete well. survey beforeproceeding to make an electrical log. It may be desirable in certaincases to make a few deviation records, then an electrical log, followedby more deviation records, etc. urements when going ,-down the bore holeand to make an electrical log on the way up, but this procedure can ofcourse be varied at will. {this advantageous feature is made possible bythe fact it is out of engage Instead of providing a plug omitted.

' .said contacts being at the surface, and he the surface of the earth,and an electrical cit-' It is customary to make the deviationmeasparatus and 1,913,293.

that the operator is always aware of the exact position of the switch38.

Many modifications in the specific embodiments describedabove willsuggest themselves to those skilled in the art. For example; the pilotlight H2 might be replaced by an ammetenand' two separate sources of thepotential might be used in place of the battery 81, one for the pilotlight circuit and one for the motor and instrument lights. Alternatingcurrent might be used equally well.

While the invention has been described above in connection with athreeconductor cable and a specific three electrode well logging circuit,other electrode configurations andcircuits may be used with equalsuccess, such as, for example, the apdisclosed in prior patents, Nos.1,819,923

Other well servicing might also be used instead of a well loggingcircuit, as will be apparent to those skilled in the art.

The modifications described above are intended to be illustrative only,intended to be limited in susceptible of numerous detail. within thescope of I claim:

1. A well surveying instrument for use with a multi-conductor cablecomprising a casing adapted to be lowered into a bore hole, a pluralityof conductors extending through the casing, means in the casing forproviding indications of the inclination of thebore hole, means in thecasing including a movable light sensitive record strip for obtaining aphotographic record of said inclination indicating means, a motor in thecasing and connected in series with one of said conductors for movingsaid record strip, a switch in the casing, having a contact memberadapted to be actuated in accordance with the displacement of saidrecordstrip to engage either of two contacts selectively, said contact memberand one of connected in the circuit of another of said conductors, andminating means in the casing connected to'said other switch contact andto a third of said conductors.

2. Apparatus for obtaining indications of the inclination of a bore holecomprising a casing adapted to be lowered into a bore hole, means in thecasing for providingindications of'the inclination and the direction ofthe. inclination of the bore hole, means in the casing'i'ncluding alight sensitive record strip for making a photographic record of saidinclination indicating any way thereby, but is changes in form and theappended claims.

means, a motor in the cming for moving said record strip, electricalmeans in the casing for il-- luminating said inclination indicatingmeans, a source of electrical energy at the surface of the earth, anelectrical circuit connecting said source with said motor andilluminating means, switching means in said circuit for connecting saidsource selectively to said motor and illuminating means, a switch in thecasing, actuated from said record strip after a predetermineddisplacement thereof has occurred, indicating means at cuit connectingsaid switch and indicating means with said source of electrical energy,whereby the exposure and advancement of the record strip may be entirelycontrolled from the surface of the eartha 4 3. In apparatus forobtaining indications of the inclination of a bore hole through anelectrical-well logging circuit, the combination a! a casing adapted tobe owered and the invention is' not electrical illuinto a bore hole,

' ber adapted casing,

means in the casing for providing indications of the inclination of thebore hole, a movable light sensitive record strip in the casing, threespaced apart electrodes disposed in the bore hole, a source ofelectrical energy at the surface of the earth, 'a pair of electricalconductors connecting said source to two of said electrodes, anelectrical motor in the casing connected in series with one of saidconductors for moving said recordstrip, a switch in the casing adaptedto be actuated in response to the displacement of said record strip,said switch having a contact memto engage a pair of contactsalternately, electrical illuminating means connected to said secondconductor and to one of said switch V contacts, an electrical connectionbetween said other switch contact and said third electrode, voltagedivider means connected to said source of electrical energy, a thirdelectrical conductor connected to said switch contact. member and tosaid voltage divider means, indicating means connected in the circuit ofsaid third conductor, and switching means associated with said secondand third conductors for controlling the connections between said sourceand the motor and illuminating means.

4. In a well surveying instrument comprising a casing adapted to belowered into a bore hole, a light sensitive record strip in the casing,an electric motor for moving said record strip and illuminating means inthe casing, the combination of a curved member mounted in the casing andhaving its upper surface formed as a segment of an ellipsoid ofrevolution, a freely rolling ball on said curved member, said curvedmember having indicia thereon indicating the angular deviation of 'theaxis of the casing from the vertical for diiferent positions of saidball,

. a compass needle universally mounted in the casing in cooperativerelation with said curved member 'and ball, switching means in thecasing adapted to be actuated by said record strip after a predetermineddisplacement thereof, indicating means at the surface of the earth forpro- "viding an indication that said predetermined displacement of therecord strip has occurred, an electric circuit connected to saidindicating means and switching means, a source of electrical energy atthe surface of the earth, an electrical circuit connected to said sourceand to said motor and illuminating means in the and switching means insaid circuit at the'surface of the earth for connecting said sourceselectivelyto said motor and switching means, whereby the exposure andthe advancement of the record strip may be entirely controlled from thesurface of the earth.

5. In apparatus for obtaining indications of the inclination of a borehole, which apparatus includes a casing adapted to be lowered into aborehole, means in the casing for providing indications of theinclination of the .bore hole, a movable light sensitive record strip,an electric motor in the casing for moving said record strip, andilluminating means in the casing for exposing said record strip, thecombination of a source of electrical energy at the surface of theearth, electrical circuits connecting said motor and illuminating meanswith said source, switching means at the surface and connected in saidcircuits for connecting said source selectively to said motor andilluminating means, signalling means at the surface of the earth, andswitching means in the casing for altering connections in a circuit tooperate said signalling means, said last named switching means beingactuatedperiodically by said record strip whenever a predetermineddisplacement thereof has occurred, whereby the advancement and exposureof the record strip may be entirely controlled from the surface of theearth.

6. In apparatus for obtaining indications of the inclination of a borehole, which apparatus includes a casing adapted to be lowered into abore hole, means in the casing for providing indications of theinclination of the bore hole, a

-movable light-sensitive record strip, an electric motor in the casingfor moving said record strip,

and illuminating means in the casing for exposing said record strip, thecombination of a source of electricalienergy at the surface of theearth, electrical circuits connecting said motor and illuminating meanswith said source, switching means at the surface and connected in saidcircuits for connecting said source selectively to said motor andilluminating means, signalling means at the surface of the earth, asignalling circuit extending from said casing to the signalling means,switching means in the casing for altering connections in saidsignalling circuit to operate said signalling means, and cam meansdriven by said record strip for actuating said last-named switchingmeans whenever a predetermined displacement of the record strip hasoccurred, whereby the advancement and exposure of the record strip maybe entirely controlled from the surface of the earth.

7. In apparatus for obtaining indications of the inclination of a borehole, which apparatus includes a casingadapted to be lowered into a borehole, means in the casing for providing indications of the inclinationof the bore hole,

a movable light-sensitive record strip, and an,

electric motor in the casing for moving said record strip, thecombination of a source of electrical energy at the surface of theearth, first and second conductors connecting said source -to the motorin the bore hole, switching means in the casing including a-contact armadapted to engage and disengage a contact intermittently, cam meansdriven by said record strip for actuating said switching means whenevera predetermined record strip displacement has occurred, electricalilluminating means connected to said contact and to said firstconductor, a third conductor extending from the contact arm of saidswitching means to the surface of the earth, an

indicating circuit connected to said first and third conductors. at thesurface of the earth, said indicating circuit including electricalindicating means and means for providing electrical energy, and atwo-position switch at the surface of the earth having contacts incircuit with said second and third conductors for disconnecting saidsource of electrical energy and said indicating means from said secondand third conductors; respectively, source of electrical energy to saidthird conductor, whereby the advancement and exposure of the recordstrip may be entirely controlled from the surface of the earth.HENRI-GEORGES DOLL.

and forconnecting said

